Hypersonic flight vehicles are a current topic of interest in both civilian and military research. NASA is currently designing a Crew Transport Vehicle (CTV) 44, 69, and Crew Exploration Vehicle (CEV) 32, to replace the space shuttle; reentry vehicles are, by definition, hypersonic vehicles. Military requirements for reconnaissance and surveillance, as well as the mission of the United States Air Force to rapidly project power globally makes the design of a hypersonic plane that can quickly traverse the globe very attractive 102. The design of hypersonic vehicles requires accurate prediction of the surface properties while in flight. These quantities are typically the heat flux, pressure and shear stress, from which the aerodynamic forces and moments can be calculated. These variables govern not only the aerodynamic performance of the vehicle, but also determine the selection and sizing of the thermal protection system (TPS), which protects the vehicle from the extreme temperatures encountered at hypersonic velocities. The geometry of a vehicle, and in particular, the nose and the leading edges of wings and other aerodynamic surfaces, is a critical consideration in a vehicle's design. Aerodynamic heating is inversely proportional to the square root of the 1 radius at the stagnation point; hence, historically most vehicles have had blunted noses and leading edges to reduce the thermal loads to acceptable levels. Recently, however, a class of materials, designated Ultra-High Temperature Ceramic (UHTC) composites, has been developed that can withstand temperatures as high as 3500 K 57, 78. Materials such as these allow the use of much sharper leading edges.


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